1. Field of the Invention
This invention relates to phase stable, liquid detergents, which contain solid oxidants, preferably sodium perborate, which maintains surprisingly good oxidative stability by the use of an alkali metal borate, boric acid, an alkali metal chloride, or a mixture thereof.
2. Brief Description of Related Art
Liquid detergents are desirable alternatives to dry, granular detergent products. While dry, granular detergents have found wide consumer acceptance, liquid products can be adapted to a wide variety of uses. For example, liquid products can be directly applied to stains and dirty spots on fabrics, without being predissolved in water or other fluid media. Further, a "stream" of liquid detergent can be more easily directed to a targeted location in the wash water or clothing than a dry, granular product.
There have been many attempts to formulate liquid detergents which contain oxidants.
For example, Krezanoski, U.S. Pat. No. 3,852,210, Lutz et al., U.S. Pat. No. 4,130,501, and Smith et al., U.S. Pat. No. 4,347,149, disclose liquid hydrogen peroxide-based bleach compositions at relatively low pH's containing relatively minor amounts of surfactants. The disadvantage with these compositions would be rather low detergency, owing to the low amount of surfactants.
Franks, U.S. Pat. No. 4,430,236, Goffinet et al., U.S. Pat. No. 4,470,919, and Smith et al., U.S. Pat. No. 4,525,291, disclose higher amounts of hydrogen peroxide and surfactant. However, in order to preserve the oxidant, the compositions generally require the addition of various stabilizing agents, such as a lower alcohol and an amino polyphosphonate (Smith et al.) or fatty acids and soluble calcium salts (Goffinet et al.).
However, none of the foregoing references, or any combination thereof, teaches, discloses or suggests that solid oxidants may be stably incorporated in a liquid detergent medium. None of the foregoing art further teaches that oxidant stability of such solid oxidants can be surprisingly well maintained by use of an alkali metal borate, an alkali metal chloride, or a mixture thereof.
Haslop et al., U.S. Pat. No. 4,618,446, disclose liquid compositions containing spherulitic formations by combining anionic and nonionic surfactants with relatively high amounts of electrolytes, e.g., sodium chloride. Although Haslop states that "Bleaches may optionally be incorporated in compositions of [its] invention . . . ," it recognizes that this is ". . . subject to chemical stability and compatibility" (Column 26, lines 11-13). Haslop even teaches away from the concept that excellent oxidant stability could result in a liquid formulation containing particulate oxidants, since Haslop suggests using "encapsulated bleaches." (Id.)